Joist suspension



Jan. 18, 1938. E. DuCODDINGTON 2,106,084

JOINT SUSPE-NS ION Filed NOV. 9, 1936 (Kw-0 w Patented Jan. 18, 1938 UNITED STATES PATENT OFFICE JOIST SUSPENSION Application November 9, 1936; Serial No. 109,990

6 Claims.

This invention relates to joists and joist suspensions for connecting transverse joist sections to supporting joists in building construction.

An important object of my invention is to provide a sawable and nailable joist of the general type disclosed in my copending applications Serial Nos. 39,025", 39,027, 39,028 and 47,867, comprising a pair of parallel chords supported in spaced relation by a web extending diagonally back and forth between the chords and rigidly connected thereto.

Another object of my invention is to introduce into trussed joists, having web members spaced at relatively wide intervals, end web members such that by a minimum amount of effort, relatively small variations in the length of the joist may be obtained. More particularly the invention aims to provide a joist of the above character which is so constructed as to permit being readily sawed off in small increments, as determined by indications carried upon opposite ends of the joist, such as slots marking the lines of severance. By this arrangement the joists may be made in standard lengths and being adapted to be cut down to a maximum extent which slightly exceeds the stud of the next shorter standard length.

Another object of my invention is to provide a joist suspension which affords sufficient flexibility of adjustment to compensate for errors arising in cutting the transverse joist sections to length or for correcting inaccuracies in the spacing of the supporting joists between which the transverse joist sections extend. The joist suspension of 35 the invention will find advantageous employment in connection with prefabricated building structures,'by-providing means for the rapid and convenient assembly of the joists by a simple mechanical operation.

The invention has for a further object to provide a strong and rigid connection between the transverse joist sections and the supporting joists.

Other objects and advantages will be apparent from the following detailed description of a preferred embodiment of the invention when considered in conjunction with the annexed drawing,

in which:

Figure 1 is a perspective view of the joist suspension showing the joists in separated relation;

Figure 2 is a perspective view of the connected joists with parts broken away for clearness;

Figure 3 is a perspective view of a hollow plate strut forming a part of the suspension assembly; and

Figure 4 is a cross-section through the supporting joist showing the joist suspension in side elevation.

In Fig. 1 is shown a transverse joist section I and a supporting joist lato which the transverse 55 joist section is to be connected. The transverse joist section and the supporting joist each comprises a pair of sheet metal tubular chords 2 of generally trapezoidal cross section, enclosing .a nailable cementitious core 2a. These chords are supported in parallel spaced relation by an open continuous web 3 of channel form bent into zigzag shape so as to extend back and forth between the chords. The opposed faces of the chordsare provided with depressions 4 extending throughout their length and the web is flattened at its points of contact with the chords. Atttheseflats the side flanges of the web are bent inwardly against the bottom of the channel so .aszto .permit the web to fit snugly within the depressions, at which points the web is welded to the chords. This type of joist is more fully described inmy copending application Serial No. 47,867, filed November 1, 1935.

Seating withinthe-depressions and reaching rbetween the two chords at an endof the joist section is a terminal block or hollow plate strut 5. As best shown in Fig. 3 the hollow plate strut .5 comprises a sheet of relatively heavygage metal bent into generally U-shape so as to provide'two .30 parallel sides5a and an intermediate :spacer portion 5b of a Width corresponding to that of the depressions 4 extending along the chords of .a joist. The hollow plate strut is provided with pairs of vertically disposed openings :6 .upon :its opposite sides. Similarly the sides Saof the hollow plate strut are provided with slots :l-extending intermediate each pair of openings 'but'terminating a spaced distance therefrom so as to leave an unmutilated web of material 'betweenthe ends 40 of the slots and the openings. Notches 8, consti- 'tuting in effect continuations ofthe slots 'Lextend from a point a spaced distance from the openings 6 to the upper and lower edges'of the hollow plate strut. Intermediate the slots 1 .the sides lia :of the hollow plate strut are "formed with inwardly pressed stiffening ribs 9.

This hollow plate strut will ordinarily be "associated with the joist section during its manufacture, or alternatively may be assembled with :the joist on the job. In either event, this assembly is accomplished by removing'the terminal diagonal leg of the web 3 inwardly of an end of the joist, sliding the hollow plate strut, closed end foremost, along the tracks defined by the depressions 4 upon the opposed faces of the chords until the spacer 5b abuts the end of the web which is joined to a chord with the open end or the hollow plate strut terminating flush with the end of the joist. The hollow plate strut is then welded, soldered or otherwise bonded to the upper and lower chords. Such welding is indicated at It) in Fig. 1 and is located between the sides of the hollow plate strut and the margins of the channels which receive the latter. The openings 6, slots 1, and notches 8 are all equidistantly spaced apart and disposed in alignment upon the opposite sides 5a of the hollow plate strut.

The function of the notches and slots in the sides of the hollow plate strut is to facilitate severance of the ends of the joist. For example when the notches and slots are spaced apart in increments of one inch, they form indications by which the workman can readily determine by inspection and without the necessity of measuring the amount of material to be trimmed off of a joist in order that it may properly fit between two supporting joists or in order that it may fulfill other conditions. So also the number of standard lengths of joists necessary to be stocked is considerably reduced because, by a judicious selection of sizes, each standard length of joist may be selectively trimmed down to a size slightly exceeding that of the next shorter length of joist. Thus in the case where the slots are one inch apart and three slots are provided in each hollow plate strut located at opposite ends of a joist, the maximum distance by which the joist is adapted to be shortened by severance is 6 inches. Under such conditions the difference in standard lengths of the joists as manufactured will be 7 inches. In trimming a joist to length it is only necessary to sever the chords as by a hack saw and complete the severance of the webs of metal between the aligned openings 6, slots 1 and notches 8.

Adapted to be attached to the supporting joist la is a pair of brackets l2, each of these brackets comprising a rectangular base plate I3 and a bearing plate M bent outwardly at right angles thereto. The brackets [2 are secured to the side of the supporting joist by means of bolts l5 passing through a pair of vertically aligned holes IS in the base plate to the opposite side of the joist. Clamping strips ll of relatively heavy gage metal are disposed upon the opposite side of the joist and are provided with a pair of suitably located holes to receive the ends of the bolts [5. The base plates l3 and clamping strips ll extend between and slightly overlap the sides of the upper and lower chords of the supporting joist,

and the ends of the bolts l5 which project beyond the clamping strips I! are screw threaded to receive clamping nuts l8 by which the base plates [3 and the clamping strips I! are drawn together into tight engagement with the joist. In order to insure an unobstructed passage for the bolts transversely of the joist at one side of the web 4, the base plate I3 is provided with duplicate pairs of holes [6 so' that under any conditions one of these pairs of holes will be disposed out of line with the web. The bearing plates are of a height corresponding to that of the hollow plate strut, and these bearing plates are similarly provided with vertically aligned pairs of openings 20, corresponding in size and location to the holes 6 in the sides of the hollow plate strut, but transversely spaced apart a distance greater than the latter holes. Bolts 2| (Figure 2) are adapted to be passed through companion pairs of holes 20 of the two bearing plates and the coinciding pairs of holes 6 of the hollow plate strut and retained by nuts 22 threaded upon the extended ends of the bolts.

In assembling the joists, the transverse joist section I carrying at each of its ends a hollow plate strut 5 will be lowered between two supporting joists la so that the ends of the transverse joist abut or substantially abut the sides of the two supporting joists. The brackets 12 will then be bolted to each of the supporting joists in a manner which has been previously described with the bearing plates I4 engaging opposite sides 50. of the hollow plate strut.

If the transverse joist be slightly overlength, it may be readily sawed off along one of the lines of severance indicated by the slots 1, it being simply necessary to saw through the chords and through the webs of metal separating the slots 7, notches 8 and openings 6 of whichever line of severance is selected. Should the transverse joist section on the other hand be found to be scant in length due either to an error in cutting or in the spacing of the supporting joists, ap-

preciable gaps between the joist section and the supporting joists is avoided by shifting the joist section to equalize the spacing at its opposite ends. Due to the difference in the spacing of the pairs of holes in the brackets and the correlated holes in the hollow plate strut, at least one of the pairs of holes of the latter will be disposed in alignment with a pair of holes in the brackets, or in any event may be brought into alignment with either of these pairs of holes by slightly shifting the transverse joist section endwise. The bolts 2| are then passed through the pairs of aligned holes in the bearing plates and the hollow plate strut and the nuts 22 tightened to cause the hollow plate strut to be firmly clamped between the bearing plates. In a similar manner the nuts I 8 upon the bolts l5 are tightened against the clamping strips I! to clamp the brackets to the supporting joist.

As will be apparent, the work of laying the joists is greatly simplified and expedited, while the connection between joists is neat, close fitting and strong. Various changes in form and design of the joist and joist suspension described above obviously may be made without departing from the spirit of my invention.

I claim:

1. A joist suspension comprising in combination a transverse joist section and a supporting joist, a pair of spaced bearing plates detachably connected to the supporting joist and projecting laterally therefrom, a hollow plate strut carried upon the end of the transverse joist section and snugly received between the bearing plates, said bearing plates and hollow plate strut being provided with pairs of holes capable of being selectively brought into alignment but being differently spaced apart, and attaching means extending through the aligned holes of the bearing plates and hollow plate strut.

2. A joist suspension comprising in combination a transverse joist section and a supporting joist, a pair of spaced bearing plates detachably connected to the supporting joist and projecting laterally therefrom, a hollow plate strut carried upon the end of the transverse joist section and snugly received between the bearing plates, said bearing plates and hollow plate strut being provided with pairs of holes capable of being selectively brought into alignment, a plurality of parallel vertically extending slots terminating intermediate the upper and lower edges of the hollow plate strut, and attaching means extending through the aligned holes of the bearing plates and hollow plate strut.

3. A joist suspension comprising in combination a transverse joist section and a supporting joist, a pair of spaced bearing plates detachably connected to the supporting joist and projecting laterally therefrom, a hollow plate strut carried upon the end of the transverse joist section and snugly received between the bearing plates, said hollow plate strut being composed of sheet metal bent into U-shape with its open end disposed toward the adjacent end of the joist section and its closed end disposed toward the remote end of the joist section, said bearing plate and hollow plate strut being provided with pairs of holes capable of being selectively brought into alignment but being differently spaced apart, and attaching means extending through the aligned holes of the bearing plates and the hollow plate strut.

4. A joist suspension comprising in combination a transverse joist section and a supporting joist, said joist section and supporting joist being of the open web type, a pair of spaced bearing plates detachably connected to the supporting joist and projecting laterally therefrom, a hollow plate strut carried upon the end of the transverse joist section and snugly received between the bearing plates, said hollow plate strut being composed of sheet metal bent into U-shape with its open end disposed toward the adjacent end of the joist section and its closed end disposed toward the remote end of the joist section, said hollow plate strut having parallel vertically extending slots located in alignment upon its opposite sides, and said bearing plates and hollow plate strut being provided with pairs of holes capable of being selectively brought into alignment but being differently spaced apart, and bolts extending through the aligned holes of the bearing plates and hollow plate strut.

5. A joist comprising a pair of sawable chords, a web extending between the chords and supporting the chords in spaced relation and termihating inwardly of an end of the joist, and a terminal block extending between the chords and occupying the space between the end of the web to the ends of the chords, said terminal block being provided with a plurality of cut-off indicators located at regularly spaced intervals longitudinally of the joist.

6. A joist comprising a pair of chords, a web extending between the chords in spaced relation and terminating inwardly of the ends of the joist, and a terminal block extending between the chords at each end of the joist and occupying the space between an end of the Web and the ends of the chords, said chords being composed of a relatively light sawable and nail penetrable sheet metal casing enclosing a core of sawable and nailable cementitious material, and said terminal blocks each being provided with a plurality of vertically disposed slots located at regularly spaced I intervals longitudinally of the joist and indicating suggested lines of severance for the joist.

EDWIN D. CODDINGTON. 

